Particulate Fuel Combustion Method and Furnace

Abstract

Method of operating a combustion furnace comprising at least one pair of particulate fuel burners positioned opposite one another across a combustion zone, whereby each burner of a pair operates in turn to generate a flame directed at the other inactive burner of the pair so as to locally overheat the burner block of the inactive burner.

1 - 19 . (canceled) 
     
     
         20 . A method of operating a furnace, comprising the steps of:
 a) providing a furnace comprising: a combustion chamber having walls defining a combustion zone within the combustion chamber, and at least one pair of particulate fuel burners, wherein:
 each pair consisting of a first particulate fuel burner and a second particulate fuel burner is equipped to inject fuel and oxidant into the combustion chamber; 
 the first and second particulate fuel burners of each pair comprising a burner block having at least one passage for transporting fuel and/or oxidant therethrough towards the combustion chamber; 
 the burner blocks of the first and second particulate fuel burners of each pair being mounted in the walls of the combustion chamber so as to be positioned opposite one another across the combustion zone; 
 the first and second particulate burner of each pair each being adapted to generate a flame in the combustion zone by:
 transporting fuel and/or oxidant through the at least one passage of the burner block, and 
 injecting the oxidant in gaseous form and the fuel in particulate form into the combustion zone for combustion therein; and 
 
   b) performing alternating first and second step, wherein
 during said first step, a flame is generated with the first particulate fuel burner of each pair in the combustion zone that is directed at the second burner block so as to cause local overheating of the second burner block of said pair, while the second particulate fuel burner of each pair does not generate a flame in the combustion zone; and 
 during said second step, a flame is generated with the second particulate fuel burner of each pair in the combustion zone that is directed at the second burner block so as to cause local overheating of the first burner block of said pair, while the first particulate fuel burner of each pair does not generate a flame in the combustion zone. 
   
     
     
         21 . The method of  claim 20 , wherein:
 in the first step, the second particulate fuel burner of each pair injects a deflecting gas into the combustion chamber so as to partially deflect the flame generated by the first particulate fuel burner of said pair back into the combustion zone, and   in the second step, the first particulate fuel burner of each pair injects a deflecting gas into the combustion chamber so as to partially deflect the flame generated by the second particulate fuel burner of said pair back towards the combustion zone.   
     
     
         22 . The method of  claim 21 , wherein the deflecting gas is flue gas recycled from the combustion zone. 
     
     
         23 . The method of  claim 20 , wherein the fuel injected by the first and second particulate fuel burners of the pair is a particulate solid fuel. 
     
     
         24 . The method of  claim 23 , wherein the particulate solid fuel is selected from the group consisting of particulate coal, pet coke and particulate combustible waste. 
     
     
         25 . The method of  claim 20 , wherein the particulate fuel injected by the first and second particulate fuel burners of the pair is a liquid fuel. 
     
     
         26 . The method of  claim 20 , wherein the first and second particulate fuel burners of each pair are oxy-fuel burners with oxidant containing at least 50% by volume of oxygen. 
     
     
         27 . The method of  claim 26 , wherein the oxidant contains at least 80% by volume of oxygen. 
     
     
         28 . The method of  claim 26 , wherein the oxidant contains at least 90% by volume of oxygen. 
     
     
         29 . The method of  claim 20 , wherein:
 the furnace comprises a multitude of said pairs of particulate fuel burners;   the combustion chamber has a first wall and a second wall, the first and second walls being positioned opposite one another across the combustion zone; and   the burner block of the first particulate fuel burner of each pair is mounted in the first wall and the burner block of the second particulate burner of each pair is mounted in the second wall.   
     
     
         30 . The method of  claim 20 , wherein:
 the furnace comprises a multitude of said pairs of particulate fuel burners;   the combustion chamber has a first wall and a second wall, the first and second walls being positioned opposite one another across the combustion zone; and   a first portion of the multiple pairs has the burner block of the first particulate fuel burner mounted in the first wall and the second particulate fuel burner ( 200 ) mounted in the second wall, and the remaining portion of the multitude of pairs has the burner block of the second particulate fuel burner mounted in the first wall and the first particulate fuel burner mounted in the second wall.   
     
     
         31 . The method of  claim 30 , wherein the first wall has a first row of burner blocks mounted therein and wherein the second wall has a second row of burner blocks mounted therein and whereby the first and second rows are alternating rows of burner blocks of first particulate fuel burners and burner blocks of second particulate fuel burners. 
     
     
         32 . The method of  claim 30 , wherein the first and second are lateral walls of the combustion chamber. 
     
     
         33 . The method of  claim 31 , wherein the first and second walls are lateral walls of the combustion chamber. 
     
     
         34 . The method of  claim 20 , wherein the first and second steps have a predetermined duration. 
     
     
         35 . The method of  claim 20 , wherein the burner blocks of the first and second burner of at least one pair are equipped with a temperature detector. 
     
     
         36 . The method of  claim 35 , wherein:
 the first step is terminated and the second step is commenced on the basis of one or more criteria selected from the group consisting of:
 the temperature detector of the burner block of the second burner detects a temperature exceeding a first predetermined upper limit, 
 the temperature detector of the burner block of the first burner detects a temperature lower than a first predetermined lower limit, and 
 the first step has reached a predetermined duration; and 
   the second step is terminated and the first step is commenced on the basis of one or more criteria selected from the group consisting of:
 the temperature detector of the burner block of the first burner detects a temperature exceeding a second predetermined upper limit, 
 the temperature detector of the burner block of the second burner detects a temperature lower than a second predetermined lower limit, and 
 the second step has reached the predetermined duration. 
   
     
     
         37 . The method of  claim 20 , wherein the furnace is a tunnel furnace. 
     
     
         38 . The method of  claim 20 , wherein the furnace is selected from the group consisting of glass melting furnaces, glass feeders or forehearths, tunnel calcination furnaces and reheat furnaces.